Autoinjector System

ABSTRACT

An autoinjector system for injecting a fluid medicament into a patient includes a re-usable autoinjector, and a disposable cassette loaded with a hypodermic syringe pre-filled with a fluid medicament. The autoinjector includes a first motor for injecting a needle of the hypodermic syringe into the patient and a second motor for expelling the fluid medicament from the syringe.

RELATED APPLICATIONS

This application claims the priority benefits of U.S. application Ser.No. 12/123,888, filed May 20, 2008 and U.S. application Ser. No.12/178,447, filed Jul. 23, 2008, the entire disclosures of which areincorporated herein by reference.

FIELD

The present disclosure relates to a system and method for injectingmedicaments into a patient from a hypodermic syringe. More particularly,the present disclosure relates to an auto-injector and a cassetteuseable with the auto-injector, which conceals the injection needle of ahypodermic syringe before and after an injection.

BACKGROUND

Pre-filled hypodermic syringes provide several advantages for thehome-use market. These advantages include that pre-filled syringes maybe prepared for each medicament with exactly the required dosage.Further, they are easily operated, by merely advancing the stopper ofthe syringe. Aside from the costs of the particular medication that isbeing used, pre-filled syringes are also economically manufactured.Consequently, all these advantages make pre-filled syringes commerciallyappealing.

Nevertheless, pre-filled syringes also have a significant drawback inthe marketplace. Specifically, many users are either frightened by anexposed needle or feel they are inherently incapable of performing aninjection. Because of aversions to exposed needles, as well as the manyhealth and safety issues that may be involved, various types ofinjectors and other devices have been developed for the specific purposeof concealing needles from the user and automating the injection task toassist the user in performing the injection.

In order to inject a fluid medicament into a patient when using ahypodermic syringe, generally three separate and distinct tasks must beperformed. These are: 1) insertion of the needle into the patient; 2)injection of the fluid medicament from the syringe into the patient; and3) withdrawal of the needle after the injection has been completed. Foreach task, the magnitude and direction of forces on the syringe, as wellas the location of their application, are different from the othertasks. For instance, compare the task of inserting the needle, with thetask of injecting the fluid medicament. Insertion of the needle requiresthat only minimal forces be applied on the syringe, and that they beapplied for only a very short period of time. On the other hand,injection of the medicament requires a much greater force be applied.Further, this force must be applied on the plunger of the syringe forwhat will typically be a relatively longer period of time. In comparisonwith both of these tasks, needle withdrawal requires the application ofa force in the opposite direction. These, and other similarconsiderations, become important when the injection process is to beautomated.

Springs for generating forces on a syringe in an automated process havebeen used heretofore for various purposes. A characteristic of springs,however, is that the magnitude and direction of a spring force are notvariable. Consequently, springs do not lend themselves for so-calledmulti-tasking operations. This is particularly so where precise controlover a syringe injection operation is required, and different magnitudeforces are sequentially required in the same direction (e.g. needleinsertion and medicament injection). This can be particularlyproblematic in situations where it may be desirable to use the samedevice, at different times, to inject different medications, withdifferent fluid viscosities.

In addition to the mechanical considerations mentioned above, the designof an auto-injector also requires user-friendly considerations. Inparticular, it is desirable that the injection needle of a syringe beoperationally concealed from the view of a user. Preferably, thisconcealment may be maintained before, during and after an injectionprocedure. Further, it is desirable that operation of the syringe belimited to only those times when the syringe is properly positioned foran injection.

Accordingly, an improved medicament injection system is needed, whichhides the syringe needle during use, is capable of accommodatingdifferent force requirements during an injection procedure, isrelatively easy and inexpensive manufacture, and is easy to use.

SUMMARY

In accordance with the present disclosure, a system for injecting fluidmedicaments into a patient from a pre-filled hypodermic syringe, employsa cassette that is pre-loaded with the pre-filled syringe. For thiscombination, the hypodermic syringe can be loaded into the cassetteduring manufacture, or be subsequently loaded by a contract serviceprovider. In either case, the syringe needle is concealed inside thecassette and hidden from the view of the end-user. Importantly, the onlypreparation required by the end-user (e.g. the patient that is toself-administer the fluid medicament) is to mount the cassette onto adrive mechanism.

Structurally, the system of the present disclosure envisions a pr-filledsyringe that will have a needle, and it will have a stopper forexpelling the fluid medicament from the syringe through the needle.Further, the pre-filled syringe will be firmly held on the cassette in aposition where the syringe needle is concealed and hidden from view. Asenvisioned for the present disclosure, the pre-filled hypodermic syringecan be firmly held in the concealed position, in any of severaldifferent ways. These include, the use of a latching mechanism, anadhesive, or a flexible abutment.

Once the cassette has been loaded with the pre-filled hypodermicsyringe, the cassette can be engaged with a drive mechanism. In detail,the drive mechanism includes two separate motors that perform twodifferent functions. A first motor is provided for engaging the syringein its concealed position where its needle is hidden. With thisengagement, the first motor then moves the syringe and its needle fromthe concealed position and into an exposed position where the needle isextended for insertion into the patient. While the needle is insertedinto the patient, a second motor is provided for pushing the stopper onthe syringe to expel fluid medicament from the syringe. After theinjection has been completed, the first motor then withdraws the syringeand its needle back into the concealed position. Importantly, after ithas been withdrawn the syringe is again firmly held in the concealedposition, inside the cassette. Thus, the needle remains hidden from viewat all times during an injection procedure. Further, as noted above, thesyringe is firmly held inside the cassette to insure the syringe needledoes not inadvertently extend from the cassette.

In operation, an end-user mounts a pre-loaded cassette on the drivemechanism. The end-user then removes a protective cover from the syringeneedle and positions the system at a site where an injection is to bemade. A button on the system is then pushed to activate the drivemechanism for an injector procedure. After the injection has beencompleted, the cassette, with its now empty syringe, can be removed fromthe drive mechanism and discarded.

In accordance with the present disclosure an autoinjector systemincludes a disposable cassette that operates in combination with areusable injector. Prior to an engagement of the cassette with theinjector, however, a pre-filled syringe is mounted and latched onto thecassette. When latched, the syringe is held on the cassette in a homeposition. For the present disclosure, this pre-filled syringe may be ofany type syringe well-known in the pertinent art that has a fluidchamber with an injection needle at its distal end, and a plunger thatcan be advanced into the fluid chamber. When the cassette, with syringe,is engaged with the injector, the system is ready for use.

Operation of the system of the present disclosure requires two separatemotors that are individually mounted on the injector. Though they aremechanically independent of each other, the respective operations ofthese two motors must be coordinated. Specifically, a first motor isused to effect movements of the entire syringe assembly (i.e. syringechamber, injection needle and plunger are all moved together). On theother hand, a second motor is employed to advance the plunger into thefluid chamber for performing an injection of a fluid medicament.

In a duty cycle of the system, the first motor moves a drive rod intoengagement with the syringe. With this engagement, the drive rod alsoreleases the latch that otherwise holds the syringe in the homeposition. After the syringe has been released, the first motor thenadvances the syringe in a distal direction on the cassette. Thismovement inserts the injection needle into a patient. Further, the firstmotor can be used to abruptly stop the needle when a specified needledepth has been achieved. The first motor can then be used to helpstabilize the needle during an injection of the medical medicament fromthe syringe.

As mentioned above, the injection of medical medicament from the syringeis accomplished using the second motor. In detail, once the needle hasbeen properly inserted into the patient, the second motor moves a pusherto urge against the plunger of the syringe to advance the plunger intothe fluid chamber of the syringe. Importantly, the second motor can beprogrammed to advance the plunger into the fluid chamber at apredetermined rate(s) for compliance with an injection protocol.

After the injection has been completed, the second motor withdraws thepusher. The first motor is then used again. Specifically, the firstmotor is now used to withdraw the injection needle from the patient, andto return the syringe to the home position on the cassette, where it isre-latched onto the cassette. The cassette can then be removed from theinjector and discarded.

In order to control the concerted operations of the first and secondmotors, the system includes a microcomputer that is mounted on theinjector. Importantly, the microcomputer operates the motors withdifferent forces, and at different speeds for different purposes. Morespecifically, the first motor must operate quickly to insert the needle(e.g. about 0.1 meters/second (m/s) to 1.0 m/s), but it does not requiremuch force to do so. Similarly, needle withdrawal by the first motorrequires a minimal force. Unlike the first motor, however, the secondmotor will typically be required to generate greater forces for theinjection of fluid medicament. And, accordingly, it will also typicallyoperate at slower speeds. Further, and most importantly, differentinjections (i.e. advancements of the syringe plunger by the secondmotor) may require different injection rates. Thus, the second motorrequires speed control provided by the microcomputer.

Together with the components mentioned above, the system of the presentdisclosure may employ a capacitance skin sensor of a type well known inthe pertinent art. If used, such a sensor will allow the user toascertain whether the system has been properly positioned for aninjection. In detail, a metal foil is positioned at the extreme distalend of the injector to establish a capacitance signal whenever the foilis in contact with a skin surface of the patient. The function of thissignal is actually two-fold. First, it can be used to prevent initialoperation, if the system is not properly positioned. And, second, it canbe used to interrupt operation of the system, if it becomes improperlypositioned during an injection.

Further disclosed herein is a system for injecting a medicament into apatient. The system comprises an injector and a medicament cassette. Themedicament cassette comprises a housing, a sleeve movable in the housingbetween first and second positions, and a syringe comprising a chamberfor containing a medicament and an injection needle extending from thesyringe chamber. The syringe chamber is at least partially disposed inthe sleeve and the injection needle has a skin penetrating end oppositethe syringe chamber. The skin penetrating end is disposed within thehousing when the sleeve is in the first position and the skinpenetrating end extends out from the housing when the sleeve is in thesecond position. The injector comprises a surface for removably mountingthe cassette thereon, and a motor driven link having a first endengageable with a portion of the sleeve when the cassette is mounted onthe surface. The link is provided for moving the sleeve from the firstposition to the second position.

Still further disclosed herein is a system for injecting a medicament.The system comprises an injector and a medicament cassette comprising asyringe for containing a medicament. The injector comprises a plunge rodfor expelling the fluid medicament from the syringe, a motor for drivingthe plunge rod, and a switch operatively coupled to the motor, forallowing a user to set the motor to one of a plurality of differentspeeds. The plurality of different speeds correspond to a plurality ofdifferent injection rates of the system.

Also disclosed herein is a medicament cassette for an autoinjector. Themedicament cassette comprises a housing, a sleeve movable in the housingbetween first and second positions, and a syringe comprising a chamberfor containing a medicament and an injection needle extending from thesyringe chamber. The syringe chamber is at least partially disposed inthe sleeve. The injection needle has a skin penetrating end opposite thesyringe chamber, the skin penetrating end disposed within the housingwhen the sleeve is in the first position and the skin penetrating endextending out from the housing when the sleeve is in the secondposition. A portion of the sleeve engages a drive link of theautoinjector, when the cassette is mounted on or in the autoinjector.

Further disclosed herein is an injector for injecting a medicament intoa patient. The injector comprises a surface for removably mounting acassette thereon, the cassette having disposed therein a sleeve holdinga syringe containing the medicament and a motor driven link having afirst end engageable with a portion of the cassette when the cassette ismounted on the surface, the link for moving the sleeve from the firstposition to the second position.

Also disclosed is a system for injecting a medicament into a patient,comprising an injector and a medicament cassette. The medicamentcassette comprises a housing and a syringe comprising a chamber forcontaining a medicament and an injection needle extending from thesyringe chamber, the injection needle having a skin penetrating endopposite the syringe chamber, the skin penetrating end disposed withinthe housing when the syringe is in a first position and the skinpenetrating end extending out from the housing when the syringe is in asecond position. The injector comprises a surface for removably mountingthe cassette thereon, a motor driven link having a first end engageablewith a portion of the syringe when the cassette is mounted on thesurface, the link for moving the syringe from the first position to thesecond position.

Also disclosed is a medicament cassette for an autoinjector, comprisinga housing and a syringe. The syringe comprises a chamber for containinga medicament and an injection needle extending from the syringe chamber,the injection needle having a skin penetrating end opposite the syringechamber, the skin penetrating end disposed within the housing when thesyringe is in a first position and the skin penetrating end extendingout from the housing when the syringe is in a second position. A portionof the syringe engages a drive link of the autoinjector, when thecassette is mounted on or in the autoinjector.

Further disclosed is a system for injecting a medicament into a patient,comprising an injector and a medicament cassette. The injector comprisesa surface for removably mounting the cassette thereon and a motor drivenlink having a first end for operating the cassette in a needle injectionmode.

Further disclosed is a system for injecting a medicament, comprising aninjector and a medicament cassette. The injector comprises a plunge rodfor expelling a fluid medicament from a syringe, a motor for driving theplunge rod, and a switch operatively coupled to the motor, for allowinga user to select one of a plurality of different medicament injectionrates of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made in detail to the aspects of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

FIG. 1 is a perspective view of an exemplary embodiment of anautoinjector system for injecting a medicament into a patient.

FIG. 2 is an exploded perspective view of a cassette of the autoinjectorsystem of FIG. 1 with a pre-loaded, pre-filled hypodermic syringe.

FIG. 3A is a sectional view of the pre-loaded cassette, as seen alongthe line 3-3 of FIG. 1, with the pre-filled hypodermic syringe in aneedled concealed (proximal) position.

FIG. 3B is a sectional view of the pre-loaded cassette shown in FIG. 3Awith the syringe in a needled extended (distal) position after drugdelivery.

FIG. 4 is an exploded perspective view of another embodiment of thecassette.

FIG. 5 is a sectional view of an alternate embodiment of the pre-loadedcassette, as seen along the line 3-3 in FIG. 1.

FIG. 6 is a perspective view of another exemplary embodiment of theautoinjector system showing the cassette engaged with the autoinjector.

FIG. 7 is an exploded perspective view of the cassette of theautoinjector system of FIG. 6 and its component elements.

FIG. 8A is a perspective view of the cassette and a motor/drive systemof the autoinjector system of FIG. 6 in position at the beginning and atthe end of a duty cycle.

FIG. 8B is a view of the components shown in FIG. 8A with the syringe inthe cassette being advanced by a first motor of the motor/drive systemfor insertion of the syringe needle into a patient.

FIG. 8C is a view of the components shown in FIG. 8B with the plunger inthe syringe being advanced by a second motor of the motor/drive systemfor injection of a fluid medicament from the syringe into the patient.

FIG. 9 is a perspective exploded view of yet another exemplaryembodiment of the autoinjector system comprising reusable autoinjectorand a corresponding disposable cassette.

FIG. 10A is a perspective top view of an exemplary embodiment of aninternal frame of an autoinjector similar to the one shown in FIG. 9with a delivery motor/drive system attached thereto.

FIG. 10B is a perspective bottom view of the internal frame shown inFIG. 10A with a injection motor/drive system attached thereto.

FIG. 10C is a perspective top view of the internal frame shown in FIG.10A with autoinjector control components attached thereto.

FIG. 10D is a perspective bottom view of the internal frame shown inFIG. 10A with autoinjector control components attached thereto.

FIG. 1A is an exploded top view of a cassette similar to the one shownin FIG. 9.

FIG. 11B is an exploded side view of a cassette similar to the one shownin FIG. 9.

FIG. 11C is an exploded bottom view of a cassette similar to the oneshown in FIG. 9.

FIG. 12 is a perspective view of the an inner sleeve and syringe of acassette similar to the one shown in FIGS. 9 and 11A-11C.

FIG. 13 is a perspective exploded view of the inner sleeve/syringe shownin FIG. 12 and a housing of the cassette similar to the one shown inFIGS. 9 and 11A-11C.

FIG. 14 is a bottom view of the cassette shown in FIG. 9.

FIG. 15 is table showing injection rates of three different samples ofan autoinjector system set at low medium and high delivery motor speedsettings for solutions of three different viscosities in centipoise.

FIG. 16 is a perspective exploded view of an alternate embodiment of thecassette that omits the inner sleeve.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary embodiment of an autoinjector systemfor injecting a medicament into a user/patient (a user of the system oranother person or animal) is shown and is designated by referencenumeral 100. The system 100 generally includes a disposable cassette 112and a re-usable drive mechanism or autoinjector 114. The autoinjector114 includes a cradle 116 that is dimensioned to receive and hold thecassette 112 on the autoinjector 114. The autoinjector 114 includes afirst (injection) motor 118 (shown in phantom) and a section (delivery)motor 120 (also shown in phantom). The motors 118 and 120 may compriseany suitable, well known type of motor including without limitation,stepper motors and reluctance motors. The motors 118 and 120 eachincludes a drive system for converting the rotary motion of the motor tolinear motion. Such drive systems include without limitation, leadscrew/worm gear drive systems, rack and pinion drive systems, and anyother linear drive or transmission system which enables the motors 118and 120 to individually exert axially directed forces on contents of thecassette 112. These forces will need to be directed substantially alongthe axis 122. Activation of the motors 118 and 120 for the generation ofthese forces is accomplished by manipulation of a button 124 providedwith the autoinjector 114.

Referring to FIG. 2, the cassette 112 comprises a housing 126 havinghollow, tubular shaped structure for holding a hypodermic syringe 128comprising an injection needle 130 that is affixed to the distal end ofa fluid chamber 132. A conventional finger grip 134 is provided at theproximal end of the fluid chamber 132. Also, a stopper or plunger 136 isdisposed in the proximal end of the fluid chamber 132 to expel fluidmedicament from the fluid chamber 132 through the needle 130. Aprotective cover 138 may be provided to cover the needle 130 when system100 is not in operational use, and a cap 140 is employed to grip theprotective cover 138.

Prior to an operation of the system 100, the cassette 112 is pre-loadedwith the syringe 128, which has been pre-filled with an appropriate doseof the desired medicament (e.g., a fluid medicament). Before pre-loadingthe cassette 112, the protective cover 138 is positioned over the needle130 on syringe 128. The pre-filled syringe 128 is then inserted into thehousing 126 through its proximal end 142. The cap 140 can then beinserted through the distal end 144 of the housing 126 to engage the cap140 with the protective cover 138.

The cassette 112 (pre-loaded with the pre-filled syringe 128) may bemounted on the autoinjector 114, as shown in FIG. 1, by merely insertingthe cassette 112 into the cradle 116 of the autoinjector. When inserted,the opposing protrusions (only protrusion 146 a is shown) formed on thehousing 126 of the cassette 112 engage with respective recesses 148 aand 148 b to stabilize the cassette 112 on autoinjector 114.

In one exemplary embodiment, as shown in FIG. 3A, the pre-filled syringeis firmly held inside the cassette 112 with the injection needle 130 ofthe syringe 128 concealed inside the cassette 112 and thereby hiddenfrom the user/patient's view (a needle concealed position or proximalposition) by opposing bumps 150 a and 150 b formed on inner surfaces ofresilient arms 152 a and 152 b, respectively, of the housing 126 of thecassette 112. The bumps 150 a and 150 b firmly hold the syringe 128 in ahome position (the needle concealed position) until resilient arms 152 aand 152 b are flexed outwardly by an axial force exerted by the syringe128, as the drive system of the first motor 118 pushes the syringe 128through the housing 126 of the cassette 112 to move the injection needle130 from the needle concealed (proximal) position into a needle extended(distal) position, as shown in FIG. 3B. In this distal position, thesyringe 128 is retained in the cassette 112 by stops 153 a and 153 bprovided on inner surfaces of the cassette housing 126, while theinjection needle 130 extends from the cassette housing 126 for insertioninto a user/patient.

In one exemplary embodiment, the drive system of the first motor 118engages the syringe 128 in a manner that allows the first motor 118 toretract the syringe 128 and thus the injection needle 130 from theextended (distal) position, thereby returning the injection needle 130to its concealed (proximal) position with the syringe 128 firmly held inthe housing 126 in the home position by the bumps 150 a and 150 b andthe resilient arms 152 a and 152 b.

In an alternative embodiment, a single motor may be used in place of thefirst and second motors 118 and 120. The use of the single motorrequires an appropriate drive or transmission which is capable ofconverting the rotary motion of the motor to linear motion andselectively applying the linear motion to the syringe 128 or the stopper136.

FIG. 4 shows an alternate embodiment of the cassette 112, which includesan inner sleeve 154 and an housing 156. The inner sleeve 154 is ahollow, substantially tube-shaped structure defining a lumen 158. Formedon the outer surface of the inner sleeve 154 is a proximal projection160 and a distal projection 162 that are axially aligned with eachother. The housing 156 defines a lumen 164 and an axially aligned slot166. Resilient arms 168 a and 168 b are formed on the housing 156 andare positioned to extend toward the proximal open end of the slot 166.The resilient arms 168 a and 168 b are respectively formed with detents170 a and 170 b and ramps 172 a and 172 b. The resilient arms 168 a and168 b and their corresponding detents 170 a and 170 b and ramps 172 aand 172 b define a latch mechanism.

The cassette of FIG. 4 is be pre-loaded with the syringe 128, accordingto one exemplary embodiment, by inserting the inner sleeve 154 into thelumen 164 of the housing 156 so that the proximal projection 160 on theinner sleeve 154 is positioned and held in the detents 170 a and 170 bof the resilient arms 168 a and 168 b, and then inserting the hypodermicsyringe 128 into the lumen 158 of the inner sleeve 154. This places theinjection needle 130 of the syringe 128 in the concealed (proximal)position within the cassette 112. Subsequently, movement of the syringe128 through the housing 156, which moves the injection needle 130 fromthe needle concealed (proximal) position to the needle extended (distal)position is accomplished by the drive system of the first motor 118. Inone exemplary embodiment, the drive system of the first motor 18 mayinclude a bar (not shown) that pushes against the proximal projection160 of the inner sleeve 154, thereby causing the arms 168 a and 168 b tospread and therefore, release the proximal projection 160 from theirgrasp. The inner sleeve 154, with syringe 128 firmly held therein, maythen be moved in a distal direction through the lumen 164 of the housing156. This distal movement continues until the distal projection 162contacts an end abutment 174 of the slot 166. The injection needled 130of the syringe 128 is now in the needled extended (distal) position.Subsequently, the drive system bar of the first motor 118 may be used toapply a pulling force on the proximal projection to withdraw the innersleeve 154 in a proximal direction through the lumen 164 of the housing156. This proximal movement continues until the proximal projection 160on inner sleeve 154 again engages with the detents 170 a and 170 b,thereby returning the syringe 128 to the home position and thus placingthe injection needle 130 into the corresponding needle concealed(proximal) position.

FIG. 5 shows yet another embodiment of the cassette 112. In thisembodiment, an adhesive 176 is disposed on the inner surface of thehousing 126 to firmly hold the syringe 128 in the needle concealed(proximal) position. The adhesive 176, or a similar type of restrainingelement, can be used either directly between the syringe 128 and thehousing 126 of the cassette 112, as shown in FIG. 5. The adhesive 176selectively releases the syringe 128 and then re-adheres to the syringe28 in response to the push and pull forces exerted on the syringe 128 bythe drive system of the first motor 118.

In one exemplary method of operation of the system 100, a pre-loadedcassette 112 is positioned in the cradle 116 of the autoinjector 114,which engages the syringe 128 (FIGS. 3A-3B and FIG. 5) or the proximalprojection 160 of the inner sleeve 154 of the cassette 112 (FIG. 4) withthe linear drive system of the first motor 118. Prior to an injection,the cap 140 is removed from the cassette 112. Because the cap 140 isattached to the protective cover 138 covering the needle 130 of thesyringe 128, the protective cover 138 is also removed. The system 100 isnow ready for an injection.

With the system 100 positioned at an injection site (not shown), thebutton 124 on autoinjector 114 is depressed. Depression of the button124 causes the linear drive system of the first motor 118 to apply apushing force to the syringe 128 (FIGS. 3A-3B and FIG. 5) or theproximal projection 160 of the inner sleeve 154 of the cassette 112(FIG. 4), to move the syringe 128 from the home position where theinjection needle 130 is in the needle concealed (proximal) position toan inject position where the injection needled 130 is in the needleextended (distal) position, thereby causing the needle 130 of syringe128 to penetrate into tissue of the user/patient for an injection. Atthis time, the linear drive system of the second motor 120 pushes on thestopper 136 of the syringe 128 to expel medicament from the fluidchamber 132 of the syringe 128. After an injection has been completed,the first motor 118 is again activated to apply a pulling force to thesyringe 128 (FIGS. 3A-3B and FIG. 5) or the proximal projection 160 ofthe inner sleeve 154 of the cassette 12 (FIG. 4), to withdraw thesyringe 128 from the inject position where the injection needle 130 isin the needle extended (distal) position to the home position, where theinjection needle 130 is in the needle concealed (proximal) position. Thecassette 112, along with the expended syringe 128, can then be removedfrom the cradle 116 of the autoinjector 114 and discarded.

FIG. 6 shows another exemplary embodiment of the autoinjector systemdesignated by reference numeral 200. As shown, the system 200 generallyincludes a disposable cassette 212 and a re-useable autoinjector 214.Further, as shown in phantom in FIG. 6, a motor/drive system 216 and amicrocomputer or controller 218 are mounted inside the autoinjector 214.The microcomputer 218 is activated by depressing a button 220 on theautoinjector 214. When activated, the microcomputer 218 controls theoperation of the motor/drive system 216 for its interaction with thecassette 212.

As shown in FIG. 7, the cassette 212 includes a housing 222, a innersleeve 224 and a hypodermic syringe 226 including a fluid chamber 228for holding a medicament, an injection needle 230, and a plunger 232that is moveable within the fluid chamber 228 to expel medicament fromthe chamber 228 through the injection needle 230. The syringe 226 isformed with an orifice 234 that allows for contact with the plunger 232.The syringe 226 is fixedly joined with the inner sleeve 224 and thiscombination (i.e. syringe 226 and inner sleeve 224) is incorporated withthe housing 222 to establish the cassette 212.

Still referring to FIG. 7, the inner sleeve 224 includes a projection orprotrusion 236. The housing 222 is formed with a fixation member 238that is dimensioned for engagement with the autoinjector 214 (FIG. 6).The fixation member 238 engages with the autoinjector 214 to positionthe cassette 212 in an operational alignment with the motor/drive system216. The cassette 212 may be fixedly held on the autoinjector 214 duringan operation duty cycle of the system 200, and selectively removed fromthe autoinjector 214 after its use.

As shown in FIG. 7, the housing 222 is formed with a latch mechanism240. The latch mechanism 240 includes a pair of opposed, resilient arms242 a and 242 b that are respectively formed with detents 244 a and 244b. As shown, the resilient arms 242 a and 242 b extend toward theproximal end of a slot 246 that extends along the side 248 of thehousing 222.

When assembled, the cassette 212 forms and integral unit and is intendedfor use only so long as there is medicament in the fluid chamber 228 ofthe syringe and, it is thereafter disposable. Prior to assembly, thefluid chamber 228 of the syringe 226 will be pre-filled with a defineddose of medicament. The pre-filled syringe 226 is then inserted into theinner sleeve 224 where it is fixedly held. Movements of the inner sleeve224 will thus result in a corresponding movement of the syringe 226. Thecombination (i.e. syringe 226 and inner sleeve 224) is then joined withthe housing 222. When so joined, the protrusion 236 on inner sleeve 224fits in the detents 244 a and 244 b between the resilient arms 242 a and242 b. Accordingly, the injection needle 230 of the syringe 226 is heldinside and concealed in the housing 222 of the cassette 212 in a needleconcealed (proximal) position. In this configuration, the cassette 212may be installed in or onto the autoinjector 214 substantially as shownin FIG. 6.

Referring collectively to FIGS. 8A-8C, one exemplary method of operationof the system 200 will now be described. Although the autoinjector 214is not shown in FIGS. 8A-8C, the cassette 212 and the motor/drive system216, shown therein, are to be considered as being operationallypositioned within the autoinjector 214 as shown in FIG. 6. Themotor/drive system 216 shown in FIG. 8A, includes a first (injection)motor 250 and section (delivery) motor 254. The motors 250 and 254 maycomprise any suitable, well known type of motor including withoutlimitation, stepper motors and reluctance motors. The motors 250 and 254each includes a drive system for converting the rotary motion of themotor to linear motion. Such drive systems include without limitation,lead screw/worm gear drive systems, rack and pinion drive systems, andany other linear drive or transmission system. The drive systemassociated with the first motor 250 includes a drive rod 252 which ismoved by the first motor 250. The drive system associated with thesecond motor 254 includes a pusher 256 which is moved by the secondmotor 254. The operations of the first motor 250 and the second motor254 are both controlled by the microcomputer 218.

In overview, a duty cycle for the system 200 may be envisioned as aseries of sequential changes in the configuration of cassette 212. Forsystem 200, these configuration changes are caused by separateoperations of the first motor 250 and the second motor 254. Incompliance with these operations, a complete duty cycle for the system200 will constitute, in order, configurations shown from FIG. 8A, toFIG. 8B, to FIG. 8C, and then in reverse order from FIG. 8C, back toFIG. RB and FIG. 8A.

FIG. 8A, shows the cassette 212 with the syringe 226 in a home position,which places the injection needle 230 in the needle concealed (proximal)position. In the home position, the protrusion 236 on inner sleeve 224is held by the latch mechanism 240 on housing 222. Consequently, theinjection needle 230 of the syringe 226 is held and concealed within thecassette 212. FIG. 8B shows the cassette 212 with the syringe 226 movedinto an injection position via the first motor 250, which advances thedrive rod 252, wherein the injection needle 230 has been extended fromthe cassette 12 through a hole 258 at the distal end 260 of theautoinjector 214 (FIG. 6). With this advancement, the drive rod 252interacts with the latch mechanism 240 to release protrusion 236,thereby allowing a distal movement of the now unlatched syringe 226 andinner sleeve 224 on the housing 222. This movement is controlled by themicrocomputer 218 and is performed with sufficient force to allow theinjection needle 230 to penetrate into the skin tissue of auser/patient. Preferably, this movement of the syringe 226 from the homeposition (FIG. 8A) to the injection position (FIG. 8B) is accomplishedat a speed of about 0.1 m/s to about 1.0 m/s. Further, the first motor250 may be pre-programmed to stabilize the syringe 226 in the injectionposition.

With the syringe 226 in the injection position (FIG. 8B), themicrocomputer 218 then activates the second motor 254 to move the pusher256 against the plunger 232 in the fluid chamber 228 (FIG. 7). Themicrocomputer 218 may be pre-programmed to advance the plunger 232 at anappropriate speed for injection of the medicament, which typicallycomprises a fluid medicament, from the fluid chamber 228.

FIG. 8C shows the autoinjector assembly 200 after completion of theinjection. As mentioned above, completion of the injection duty cyclerequires the pusher 256 to be withdrawn. This withdrawal of the pusher256 is accomplished by the second motor 254. Once the pusher 256 hasbeen withdrawn (FIG. 8B), the first motor 250 is again activated by themicrocomputer 218 to withdraw the drive rod 252. The drive rod 252 thenpulls the protrusion 236 back and into engagement with the latchmechanism 240, thereby placing the syringe 226 in the home position andthe injection needle 230 in the needle concealed (proximal) position.The cassette 212 can then be removed from the autoinjector 214 anddiscarded.

As an additional feature of the system 200, a sensor 262 may be providedat the distal end of the autoinjector 214. In one exemplary embodiment,the sensor 262 is positioned adjacent the hole 258 of the cassette 212.The sensor 262, in one exemplary embodiment, is of a type that willreact to capacitance that can be measured between the sensor 262 and theskin of the user/patient. The sensor 262 determines when theautoinjector 214 is in physical contact with a user/patient's skin. Themicrocomputer 218 will operate a duty cycle for the system 200 only whensuch contact is indicated. Otherwise, there can be no operation of thesystem 200.

FIG. 9 shows yet another exemplary embodiment of the autoinjector systemgenerally designated by reference numeral 300. The system 300 generallyincludes a disposable cassette 312 and a re-useable autoinjector 314.The autoinjector 314 includes a housing 315 having a cut-out 315 a forreceiving the cassette 312. The autoinjector housing 315 furtherincludes a recess 315 b for receiving a pair of opposing, lateral tabs312 a formed on a proximal end of the cassette 312, when the cassette312 is positioned in the cut-out 315 a of the autoinjector housing 315.The recess 315 b of the autoinjector housing 315 and the lateral tabs330 a of the cassette 312 cooperate to securely retain the cassette 312on the autoinjector 314 and to prevent longitudinal movement of thecassette 312 when the autoinjector 314 is operated. The autoinjectorhousing 315 also includes an injection button 320 for activating thesystem 300 and a plurality of indicator lights 321 (e.g., LEDs) forindicating the status of the system 300. A skin sensing sensor 374 isprovided at a distal end of the autoinjector 314 for sensing when thedistal end of the autoinjector 314 is in physical contact with auser/patient's skin. The autoinjector system 300 will operate only whensuch contact is indicated. The cassette 312 includes a cap 340 insertedthrough an aperture (not visible) in a distal end of the cassette 312,which is used for gripping a protective needle shield that covers aninjection needle of a syringe contained within the cassette 312, as willbe explained in greater detail further on.

Referring now to FIGS. 10A-10D and initially to FIG. 10A, theautoinjector 314 includes an elongated internal frame 316, which isrigidly secured within the autoinjector housing 315 (FIG. 9). The frame316 includes a cassette support section 316 a and motor/drive system andcontroller (MDC) support section 316 b. The cassette support section 316a forms the bottom of the housing cut-out 315 a and defines a mountingsurface for the cassette 312 (FIG. 9). A motor/drive system 349 isrigidly mounted to MDC support section 316 b of the internal frame 316.The motor/drive system 349 includes a first (injection) motor 350 (FIG.10B) and a second (delivery) motor 354 (FIG. 10A). The first and secondmotors 350, 354 may comprise any suitable well-known type of motorincluding, without limitation, stepper motors and reluctance motors.Each of the first and second motors 350, 354 is associated with a drivesystem for converting the rotary motion of the motor to linear motion.Such drive systems include, without limitation, lead screw/worm geardrive systems, rack and pinion drive systems, and any other linear driveor transmission system that is capable of converting rotary motor motioninto linear motion. As shown in FIG. 10B, the first motor 350 isassociated with a rack and pinion drive system 352 including a rackmember 352 a and a pinion 353 b, and as shown in FIG. 10A, the drivesystem associated with the second motor 354 comprises a lead screw drivesystem 356 comprising a gear drive 356 a and lead screw 356 b.

Referring again to FIG. 10B, the distal end of the rack member 352 b ofthe rack and pinion drive system 352 forms a drive link 352 c. As shownin FIG. 9, the drive link 352 c has a free end 352 d that extends upthrough a longitudinally extending, elongated opening 316 b in thecassette support section 316 a to operate a syringe insertion mechanismof the cassette 312. When the first motor 350 is operated, the rack andpinion drive system 352 moves the drive link 352 c in a linear mannersuch that the free end 352 d thereof moves distally and proximally inthe longitudinal opening 316 b of the cassette support section 316 a. Afirst position sensor 353 is provided for sensing the position and speedof the drive link 352 c, as will be explained further on.

Referring again to FIG. 10A, the lead screw 356 b of the lead screwdrive system 356 drives an elongated pusher 356 c. The elongated pusher356 c has a free end 356 d which operates a medicament deliverymechanism of the cassette 312. When the second motor 354 is operated,the lead screw drive system 356 moves the pusher 356 a in a linearmanner such that free end 356 d thereof moves longitudinally within theautoinjector 314 in a distal or a proximal direction. A second positionsensor 355 is provided for sensing the position and speed of the pusher356 a, as will be explained further on.

Referring now to FIG. 10C, the MDC support section 316 b of the internalframe 316 also supports certain control components of the autoinjector314. These control components include a printed circuit board assembly318 which defines a microcomputer or controller 319. The printed circuitboard assembly 318 includes the injection button 320 and the indicatorlights 321 described earlier, and an audible indicator in the form of apiezo-buzzer 322. The controller 319 executes one or more pre-determinedprograms that control the operation of the first and second motors 350and 354. A power supply 323 for powering the first and second motors 350and 354, and all the control components of the autoinjector 314, is alsosupported by the MDC support section 316 b of the internal frame 316. Inone exemplary embodiment, the power supply 323 comprises, withoutlimitation, a control circuit, such as a step-up DC to DC convertor, anda battery, such as a rechargeable lithium battery.

As shown in FIG. 10D, the cassette support section 316 a of the internalframe also supports certain control components of the autoinjector 314.These control components include a cassette detection switch 370, aspeed selection switch 372, and the earlier described skin sensor 374.The power supply 323 also supports the power requirements of thesecontrol components. A flexible interconnect 371 is provided forconnecting the cassette detection switch 370, the speed selection switch372, and the skin sensor 374 with the printed circuit board assembly318.

As shown in FIG. 9, the cassette detection switch 370 is actuated, inone exemplary embodiment, by an actuator button 370 a that extendsthrough an aperture in the cassette support section 316 a and engagesthe cassette 312 when same is mounted on the cassette support section316 a. The speed selection switch 372 may be actuated by a button orlike actuator 372 a extending through another aperture in the cassettesupport section 316 a. A distal end 374 a of the skin sensor 374 forms adistal end of the autoinjector housing 315 so that it can make contactwith a user/patient's skin.

Referring collectively to FIGS. 11A-11C, the cassette 312 includes ahousing 330, an inner sleeve 331 slidably moveable in the housing 330, ahypodermic syringe 326 fixedly disposed in the inner sleeve 331, and theearlier described cap 340. The syringe 326 includes a fluid chamber 326a pre-filled with a predetermined dose of a fluid medicament of apredetermined viscosity, an injection needle 326 b (shown with brokenlines) extending from a distal end of the fluid chamber 326 a, aremovable needle shield 326 c covering the injection needle 326 b, and aplunger 326 d moveable within the fluid chamber 326 a for expellingmedicament from the chamber 326 a through the injection needle 326 b.The viscosity of the fluid medicament typically ranges between about 1centipoise to about 320 centipoise, although syringes with fluidmedicaments having viscosities greater than 320 centipoise may also beused by appropriate selection of the second motor 354 and/or drivesystem 356.

As shown in FIG. 12, the inner sleeve 331 includes a pair of lockingdetents 331 a formed on a proximal end of the inner sleeve 331. Thelocking detents 331 a are configured for engaging a finger flange 326 eformed on the proximal end of the fluid chamber 326 a of the syringe326, to fixedly retain the syringe 326 in the inner sleeve 331.

As collectively shown in FIGS. 13 and 14, one of the locking detents 331a of the inner sleeve 331 includes a projection or protrusion 331 bwhich engages a latch mechanism 360 formed on the cassette housing 330.The latch mechanism 360 includes a pair of opposed, resilient lockingarms 360 a that extend proximally from the proximal end of alongitudinally elongated slot 361 formed in a side of the housing 330.The locking arms 360 a define locking detent slots 360 b through whichthe protrusion 331 b extends.

The cassette 312 is assembled, in one exemplary embodiment, by firstinserting the pre-filled syringe 326 into the inner sleeve 331 so thatthe finger flanges 326 e of the fluid chamber 326 a are lockinglyengaged by the locking detents 331 a. The inner sleeve 331 with thepre-filled syringe 326, is then inserted into the housing 330 of thecassette 312 so that the protrusion 331 b of the inner sleeve 331spreads apart- and slides between the locking arms 360 a of the housing330 and then enters the detents slots 360 b of the locking arms 360 a,where it is latched. Once assembled, the syringe 326 is now in a homeposition with the injection needle 336 b of the syringe 326 concealed inthe housing 330 of the cassette 312 in a needle concealed (proximal)position. In an alternate embodiment, the cassette 312 is assembled byfirst inserting an empty inner sleeve 331 into the housing 330 of thecassette 312 and then inserting the pre-filled syringe 326 into theempty inner sleeve 331.

The first position sensor 353 is provided for sensing the position andspeed of the drive link 352 c. The position information provided by thefirst position sensor 353 may be used, in one exemplary embodiment, foridentifying when the syringe 326 is in the home position and fordetermining when the syringe 326 is in a brake position, i.e., aposition within the cassette just prior to the needled extended (distal)position. The syringe typically enters the brake position just after theinjection needle 326 b has penetrated the user/patient's skin. The brakeposition information allows the controller 319 to stop the first motor350 quickly and in a manner that minimizes shock and vibration, when theinner sleeve 331/syringe 326 hit an end stop which defines the injectionposition. The speed information provided by the first position sensor353 may be used for maintaining the speed of the syringe moving from thehome position to the injection position.

The speed selection switch 372 has two or more settings, each of whichcorresponds to a different, user/patient selectable medicament injectionspeed (measured in seconds). This allows selection of a medicamentinjection speed that is most comfortable for the user/patient. In oneexemplary embodiment, when the user/patient selects one of the two ormore medicament injection speeds using the actuator 372 a of the speedselection switch 372, the user/patient is actually setting the voltageapplied to the second motor 354 to one of two or more differentvoltages. The actual medicament injection speed or speed of delivery,however, depends on the load force experienced by the second motor 354(i.e., the load force applied to the plunger 326 d by the pusher 356 c).The load force, in turn, depends on the gauge and/or length of theinjection needle, medicament viscosity, plunger/fluid chamber friction,motor and drive system tolerances, and cassette tolerances, and othersystem factors. When the load force experienced by the second motor 354increases, the speed of the second motor 354 will decrease at the fixedvoltage setting thereby decreasing the delivery time/rate of theautoinjector system 300. Similarly, when the load force experienced bythe second motor 354 decreases, the speed of the second motor 354 willincrease at the fixed voltage setting, thereby increasing the deliverytime/rate of the autoinjector system 300. Therefore, in one exemplaryembodiment, the controller 319 of the autoinjector 314 is pre-programmedwith a feedback control program that compensates for the load forcevariations experienced by the second motor 354, thereby maintaining themedicament injection speed of the second motor 354. Accordingly, theautoinjector system 300 is capable of providing consistent deliverytimes/rates for each speed setting of the second motor 354. In oneexemplary embodiment, the feedback control program executed by thecontroller 319 maintains the speed setting of the second motor 354 bymeasuring the speed of the pusher 356 a via the position sensor 355 andthen, increasing or decreasing the voltage of the second motor 354 inreal-time to maintain a constant pusher speed and therefore provide aconstant delivery time/rate for the selected speed setting.

The following discussion describes one exemplary method for operatingthe autoinjector system 300. First, the user/patient sets the actuatorof 372 a the speed switch 372 to desired speed setting. The speed switch372 allows the user/patient to set the second motor 354 to one of aplurality of different medicament injection rates (in seconds) of theautoinjector system 300. FIG. 15 is a table showing injection rates (inseconds) of three different samples (CM2-1, CM2-2, CM2-3) of theautoinjector system 300 set at low, medium, and high delivery motorspeed settings for solutions of three different viscosities incentipoise (cP) (1 cP, 19 cP and 29 cP). In one exemplary embodiment,the second motor 354 and drive system 356 are selected to exert up toabout 34 pounds of force on the plunger 326 d of the syringe 326 (whichequates to about 700 psi inside of the fluid chamber 326 a of thesyringe 326). In other embodiments, the second motor 354 and drivesystem 356 may be selected to exert more than 34 pounds of force on theplunger 326 d of the syringe 326.

Next, the cassette 312 is mounted onto the autoinjector 314 by placingthe cassette 312 into the cut-out of the autoinjector housing 315 sothat the cassette 312 rests on the cassette support member 316 a withthe lateral tabs 330 a of the cassette housing 330 disposed in therecess 315 b of the autoinjector housing 315, (FIG. 9). When so mounted,the cassette 312 depresses the actuator 372 a of the cassette detectionswitch 372 and the protrusion 331 b of the cassette inner sleeve 331engages the free end 352 d of the drive link 352 c. With the cassettedetection switch actuator 372 a depressed, the controller 319 will causeaudible indicator 322 to sound and the indicator lights 312 to blink ina manner which indicates that the system is ready for use. Theuser/patient then removes the cap 340 from the cassette 312, therebyremoving the needle shield from the syringe 326 and withdrawing it frominside the cassette 312. Next, the user/patient places the distal end ofthe autoinjector 315 against the user/patient's skin. If the skin sensorsenses the user/patient's skin, the controller 319 will cause theindicator lights to light steadily, indicating to the user/patient thatthe autoinjector system 300 is ready to inject. The user/patient startsthe injection by pressing the injection button 320 which energizes thefirst motor 350 in a first rotary direction, which advances the drivelink 352 c in the distal direction thereby unlatching the protrusion 331b of the inner sleeve 331 from the latch mechanism 360, thereby allowinga distal movement of the now unlatched inner sleeve 331 containing thesyringe 326, relative to the cassette housing 330. The drive link 352 c,therefore, moves the syringe 326 from the home position, where theneedle 326 b is in the needle concealed (proximal) position to theinjection position, where the needle 326 b is in a needle extended(distal) position and penetrating into the skin tissue of theuser/patient. The first motor 350 and drive system 352 are both selectedto provide a syringe injection speed, (the speed of the syringe movingfrom the home position to the injection position) of about 0.01 m/s toabout 5.0 m/s, although other syringe injection speeds are possible byselection of an appropriate motor and/or drive system. In otherembodiments, the syringe injection speed ranges between about 0.1 m/s toabout 1.0 m/s. In some embodiments, a second speed position switch (notshown) may be provided for allowing the user/patient to select betweentwo or more syringe injection speeds, to make the needle injection morecomfortable.

With the syringe 326 now in the injection position, the controller 319energizes the second motor 354 in a first rotary direction, whichadvances the pusher 356 c in the distal direction against the plunger326 d in the fluid chamber 326 a of the syringe 326 to inject the fluidmedicament from the fluid chamber 326 a of the syringe 326. In oneembodiment, the controller 310 pauses the autoinjector 314 aftercompletion of the fluid medicament injection to allow pressure todissipate in the syringe 326 so that all the medicament is delivered andno “dribbling” of medicament occurs. Upon completion of the fluidmedicament injection, the controller 319 energizes the second motor 354in a second rotary direction, which pulls the pusher 356 c in theproximal direction, thereby partially withdrawing the pusher 356 c fromthe fluid chamber 326 a of the syringe 326 to allow the injection needleto be withdrawn from the user/patient. Once the pusher 356 has beenpartially withdrawn, the controller 319 energizes the first motor 350 ina second rotary direction, which pulls the drive link 352 c back in theproximal direction. Because the free end of the drive link 352 c iscoupled to the protrusion 331 b of the inner sleeve 331, the drive link352 c pulls the inner sleeve 331 containing the spent syringe 326 backto the home position where the protrusion 331 b is again latched by thelatch mechanism 340, thereby placing the injection needle 330 in theneedle concealed (proximal) position again. The controller 319 thenenergizes the second motor 354 again in the second rotary direction tofully withdraw the pusher 356 c from the fluid chamber 326 a of thesyringe 326. The cassette 312 can now be removed from the autoinjector314 and discarded.

The autoinjector system 300 may be suitably adapted to provide anydesired medicament injection rate. In one exemplary embodiment of theautoinjector system, the medicament injection rates range between about2.0 seconds and about 15.0 seconds.

In one exemplary embodiment of the autoinjector system, the medicamentcomprises a fluid medicament having a viscosity of about 1 centipoiseand the medicament injection rates range between about 2.9 seconds andabout 5.0 seconds.

In another exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity of about 19centipoise and the medicament injection rates range between about 4.4seconds and about 9.6 seconds.

In a further exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity of about 29centipoise and the medicament injection rates range between about 7.5seconds and about 11.8 seconds.

In one exemplary embodiment of the autoinjector system, the medicamentcomprises a fluid medicament having a viscosity of about 19 centipoise.

In another exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 1 centipoise and about 320 centipoise.

In still another exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 5 centipoise and about 40 centipoise.

In yet another exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 10 centipoise and about 35 centipoise.

In a further exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 15 centipoise and about 30 centipoise.

In still a further exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 20 centipoise and about 25 centipoise.

In still a further exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 16 centipoise and about 42 centipoise.

In yet a further exemplary embodiment of the autoinjector system, themedicament comprises a fluid medicament having a viscosity rangingbetween about 1 centipoise and about 29 centipoise.

FIG. 16 shows an alternate embodiment of the cassette designated byreference numeral 326′. The inner sleeve shown in the embodiment ofFIGS. 11A-11C and 12-14 has been omitted and the fluid chamber 326 a′ ofthe syringe 326′ has been provided with a projection or protrusion 326 pthat engages the latch mechanism 360 formed on the cassette housing 330.The free end 352 d of the drive link 352 c of the autoinjector 314 (FIG.9) engages the protrusion 326 p to move the syringe 326′ from the homeposition to the injection position.

Although the autoinjector system and its elements have been described interms of exemplary embodiments, it is not limited thereto. Rather, theappended claims should be construed broadly, to include other variantsand embodiments of the autoinjector system and its elements, which maybe made by those skilled in the art without departing from the scope andrange of equivalents of the system and its elements.

1-93. (canceled)
 94. An injector for injecting a medicament into apatient, the injector comprising: a surface for removably mounting acassette thereon, the cassette having a syringe containing themedicament movably disposed therein; and a motor driven link having afirst end engageable with a portion of the cassette when the cassette ismounted on the surface, the link for moving the syringe from a firstposition to a second position.
 95. The injector according to claim 94,further comprising a motor driven plunge rod for expelling themedicament contained in the syringe at a specified medicament deliveryrate.
 96. The injector according to claim 95, further comprising a motorfor driving the plunge rod, the motor being speed adjustable to allow auser to select the medicament delivery rate.
 97. The injector accordingto claim 96, further comprising a controller for automaticallymaintaining the selected medicament delivery rate.
 98. The injectoraccording to claim 95, further comprising a second motor for driving thelink.
 99. The injector according to claim 94, further comprising a motorfor driving the link.
 100. The injector according to claim 94, furthercomprising: a housing; and a frame disposed with the housing, the frameincluding a cassette support portion providing the surface.
 101. Theinjector according to claim 100, further comprising a rack and piniondrive system.
 102. The injector according to claim 101, wherein the rackand pinion drive system includes a rack member, the rack member having adistal end forming the link.
 103. The injector according to claim 102,wherein the link comprises a tab extending through an opening in thecassette support portion to engage the cassette.
 104. The injectoraccording to claim 101, further comprising: an injection motor operablycoupled to the rack and pinion drive system; and a delivery motor. 105.The injector according to claim 104, further comprising a lead screwdrive system coupled to the delivery motor.
 106. The injector accordingto claim 104, wherein the frame further includes a drive supportportion, the injection motor and the delivery motor being mounted to thedrive support portion.
 107. The injector according to claim 104, furthercomprising a controller configured to execute programs that control theoperation of the injection motor and the delivery motor.
 108. Theinjector according to claim 107, further comprising a speed selectionswitch, the controller configured to control operation of the deliverymotor according to a selected medicament delivery rate from the speedselection switch.
 109. The injector according to claim 107, furthercomprising a skin sensor accessible on an exterior of the housing, theskin sensor configured to indicate to the controller when the skinsensor is in physical contact with a patient's skin.
 110. The injectoraccording to claim 109, further comprising indicator lights, thecontroller configured to illuminate the indicator lights in response tothe skin sensor indicating physical contact with the patient's skin toindicate that the injector is ready to inject.
 111. The injectoraccording to claim 107, further comprising an injection button foractivating the injector.
 112. The injector according to claim 100,further comprising a cassette detection switch.
 113. The injectoraccording to claim 112, wherein the cassette detection switch includesan actuator disposed adjacent to the cassette support portion, theactuator configured to be actuated by a cassette mounted on the cassettesupport portion.